Dylan's comment is very interesting. IMHO there are plenty of opportunities in EDA and semi for the iPhone platform. The key is that these opportunities are not in "design". They are in the areas where back-of-the-napkin type, first-order estimates are being made: pricing, power consumption, performance modeling (for a high level system). In these areas, the input is a small set of parameters, though they can be highly inter-related and even diametrically opposing.
The persistent datastore and text editing capabilities on iPhone are still too limited to actually write an RTL file on the device. But as long as estimates can be done only using a dozen of parameters, iPhone is a great platform for "estimates" and modeling.
I do want to add that my comment above is entirely based on the assumption that the application is native on iPhone. One can always use VNC (like Robert's, in his comment) to fake a tool running on iPhone). With VNC and SaaS in general, anything can be done on iPhone :-)

I haven't had the pleasure of meeting Robert Dwyer, but after seeing his video clip, I wanted to add a comment that iWafer, as opposed to what Robert showed, is not a demo running on a VNC session. IWafer is a) fully native on the iPhone platform, and b) something that can be used in real-life die/wafer size/price cases. It has been used by many folks in their day-to-day tasks.
The inspiration came from talking to ASIC, foundry, and design services folks who need to be able to quote estimated die prices over a lunch conversation.

I can't speak for Michael. Perhaps that is where he got the inspiration. But I am curious to know if readers see other opportunities for iPhone apps that relate directly to EDA or semiconductor manfacturing. Any thoughts?